Windows Server 2008 RDP issue

I recently installed our 1st Micro. Win. Server 2008 Ent. Edition on a server. I have it configured so I can log on remotely via RDP as the server administrator. I can’t figure out how to allow domain admins to log in remotely via RDP. I’ve added domain admins as Admin to the machine, I’ve added Domain admins to RDP. I am obviousl missing a step. Please help.

Thank you,